Before we start exploring the various capabilities built into Kubernetes for scaling and updates, we will need a new example environment. We are going to use a variation of our previous container image with a blue background (refer to the v0.1 and v0.2 (side by side) image, later in this chapter, for a comparison). We have the following code in the pod-scaling-controller.yaml file:

apiVersion: v1 
kind: ReplicationController 
metadata: 
  name: node-js-scale 
  labels: 
    name: node-js-scale 
spec: 
  replicas: 1 
  selector: 
    name: node-js-scale 
  template: 
    metadata: 
      labels: 
        name: node-js-scale 
    spec: 
      containers: 
      - name: node-js-scale 
        image: jonbaier/pod-scaling:0.1 
        ports: 
        - containerPort: 80

Save the following code as pod-scaling-service.yaml file:

apiVersion: v1 
kind: Service 
metadata: 
  name: node-js-scale 
  labels: 
    name: node-js-scale 
spec: 
  type: LoadBalancer 
  sessionAffinity: ClientIP 
  ports: 
  - port: 80 
  selector: 
    name: node-js-scale

Create these services with the following commands:

$ kubectl create -f pod-scaling-controller.yaml
$ kubectl create -f pod-scaling-service.yaml